Mammalian hair on the scalp and body biologically provides protection for important organs such as the head, the chest or the brisket, and the arm and legs. In recent years, however, hair on the human arms and legs is not considered to be preferred from the standpoint of makeup, beauty and external attraction, resulting in a tendency to remove hair from the body.
Conventionally known removal methods of hair from the body include, in addition to mechanical removal methods making use of a shaver, tweezers or the like, depilating methods which chemically decompose hair fibers or prevent, inhibit or retard hair growth. Such removal methods of body hair, however, tend to give physical or chemical irritations to the skin. Even from the standpoint of hair growth inhibition, they are not considered to be sufficient yet so that upon an elapsed time of a certain period, body hair must be removed again. There is, accordingly, an outstanding desire for a reduction to the irksomeness of removal of hair from the body.
In animals, on the other hand, paying attention to the existence of hair removing activity on epidermal growth factor (EGF), attempts to use EGF as wool harvesting preparations are finding practical utility. This application has merits in that sheep are free of potential cut damages and wool is improved in both yield and quality, for example, wool so harvested is uniform in length and is round at free ends. Development of a safe and economical depilatory is also meaningful in such a field.
An object of the present invention is to provide a depilatory and external preparation, each of which inhibits growth of hair in mammalian skin and is useful as a drug, cosmetic or animal drug.